radioactive contaminartion

• irradiation is when an

  object or person is exposed to a radioactive source without direct contact
• how is irradiation useful

  cancer treatments

  removing bacteria from fruits

  sterilize equipment
• Irradiation can be used to preserve fruit sold in supermarkets by

  exposing the fruit to a radioactive source
• in medical irradiation

  • beams of gamma rays, called gamma knife, are used to kill cancerous tumours deep inside the body

  
• the beams in medical irradiation

  are aimed at the tumour from many different directions to maximise the dose but to minimise the dose on the surrounding soft tissue.

  This technique can damage healthy tissue, so careful calculations are done to establish the best dose - enough to kill the tumour, but not so much so that the healthy tissue is damaged.
• In medical applications that involve using radioactive source to ensure that irradiation does not cause any long-term effects. They consider:

  the nature of decay 

  the half life

  the toxicity
• considering the half life in the medical industry is essential to see how

  long it takes for the isotope to produce useful measurements, but short enough for the radioactive sources to decay to safe levels soon after use
• contamination is when a person or an object is exposed to the source for a longer period of time through


  direct contact

  ingesting

  inhaling
• radioactive tracers are injected into the body to see

  possible blockages

  
• radioactive tracers are used to find

  leaks in water pipes

  
• irradiation is good because

  • sterilisation can be done without high temperatures
  • it can be used to kill bacteria on things that would melt

  
• the disadvantages of using contamination are:

  • it may not kill all bacteria on an object
  • it can be very harmful - standing in the environment where objects are being treated by irradiation could expose people’s cells to damage and mutation

  
• contamination is also used to diagnose condition and check for

  pathogens
• irradiation completely stop if the source is

  removed
• irradiation can be stopped

  blocked with suitable shielding or moving away.

  
• if an object is contaminated it very difficult to

  remove all traces of the radioactive isotope
• A contaminated object will be radioactive for as long as

  the source is on or in it.